Possible Experience

The notions of possible experience and conditions on experience play a cru- cial role in Kant’s views about modality. To clarify, possible experience is not to be understood as what we could experience if “could” is taken to mean something like “practically possible” or “physically possible”. Two examples spring to mind.

First, Parsons (1964) has highlighted a problem for reconciling the notion of possible experience with Kant’s comments on infinity. On the one hand, he claims, Kant’s theory of intuitions includes the claim that space and its contents are infinitely divisible and indefinitely complex.

It follows from the fact that the empirical objects of perception are in an infinitely divisible space that they are indefinitely com- plex. For the spatial region which an object occupies can be divided into subregions, which again can be so divided, and so on. (Parsons, 1964, p. 185)

The objects of empirical perception are objects of possible experience, given that they are objects of actual experience. Parsons then raises problems for the idea that we could perceive this infinite complexity in objects of possible experience. Given the perceptual powers we in fact have, we would not be able to perceive complexity beyond certain limits.

[Kant] must hold that we represent objects as being in a space and time having parts which are beyond the experience of a thoroughly finite being, and that this arises from the form of our sensibility. But this cannot be justified phenomenologically. (Parsons, 1964, p. 196)

If “practically possible” was the notion of possible experience in play, the complex features that we are unable to perceive could not count as part of possible experience as opposed to the claims presented as part of the theory of intuition. ‘Thus it appears that the “possibility of experience” for Kant must extend beyond what is practically possible for the sort of being we have reason to think we are’ (1964, p. 193). The problem is to make sense of what “could” means in “what we could experience”.

A second example concerns Dummett’s notion of a verification transcen- dent statement, a statement whose truth or falsity we would never be able to verify.11 Examples include statements about the past for which no evi- dence remains, such as “There were 101 hairs on Julius Caesar’s head when he died”; statements about non-manifested character traits, such as “Jones was brave” for Jones who is now dead and who never showed any behaviour pertaining to bravery or cowardice throughout his life; and certain state- ments about the future such as “There will never be a city built on this spot”, for which we would need experience infinitely extended forward in time. We could have no experience to confirm or disconfirm these state- ments (they transcend verification). But the intuition is that Jones could have been brave, or that it is possible that Julius Caesar had 101 hairs on his head when he died, or that it is possible that a city will never be built on this spot. Indeed, it would be strange to claim that it is impossible that Julius Caesar could have had 101 hairs on his head when he died, even if you agree that the statement “Julius Caesar had 101 hairs on his head when he died” cannot be verified. So although in one sense we could not experience Jones’s bravery or the number of hairs on Julius Caesar’s head when he died, if we want to count these statements as possibly true, we need a notion of possible experience that admits them.

I think the response to these problems is to construe possible experience, not as dependent on the circumstances in which one could have a particular experience of some thing, but rather as dependent upon universal rules and features. Practically speaking, I could not find myself in a circumstance where I would be able to verify that Jones was brave, but Jones being brave is compatible with universal rules and features of experience, e.g. the notion of Jones as a human being with a particular character trait is not logically contradictory and does not violate certain laws of physics. Jones’s being brave qualifies as something that could feature in experience given its com- patibility with certain rules and features; this does not imply that one can verify (or falsify) that Jones was brave. Possible experience is then experi- ence which is compatible with certain universal conditions, not experience which one could have in some practical sense of “could”.

Defining modality whilst leaning heavily on a notion of “possible expe- rience” might seem circular. However, the shape of the account sketched

so far should go some way to alleviating this concern. First, if RM can in general stand up to its main objections, this reduces the task of explaining modality to the nature of logical modality and the status of the base class of propositions from which interesting kinds of relative necessity follow. The notion of “possible experience” then enters in when giving a Kantian ac- count of the base class of propositions from which Kant’s “real” necessities follow. This is not immediately circular, because the conditions on experi- ence involved in the notion of “possible experience” are not so much defined in terms of real possibility, but in terms of the categories.

In summary, Kant’s notion of possible experience should not be under- stood in terms of what we could experience practically speaking, but in terms of conformity to certain conditions or constraints. The basic notion is not really, after all, possible experience, but rather certain constraints on experience, necessary conditions to which experience must conform. Pos- sible experience is then simply experience which conforms to them. These constraints, for Kant, are provided by the a priori or “pure” elements of our cognitive faculties that contribute to the nature of experience, without which we could not have the kind of experience that we in fact have. (See section 4.3.3 below for some alternative ways to understand these elements without having to rely on the transcendental idealist explanation in terms of cognitive faculties.) This leaves open a huge question concerning how we might argue for there being such conditions on possible experience, and how we might discover what they are. The answer to these questions is part of what Kant tries to achieve in the first Critique. For now I will grant the resulting view. I will consider why we might want to be in broad agreement with Kant on this in Chapter 5.